2008 Vol. 1, No. 1

paper
Realization of high resolution visible earth observation on geostationary earth orbit
YU Qian-yang, QU Hong-song
2008, 1(1): 1-12.
Abstract(3819) PDF 397KB(3439)
Abstract:
High resolution visible earth observation on the Geostationary Earth Orbit(GEO) has a series of unique advantages over that in the other orbits. However, long range and high resolution visible observation requests a large primary mirror more than 20 m in the diameter. The traditional Space Telescope (ST) with such a large primeny mirror can not be launched to GEO, for its total mass is more than 1 000 t. An unsupported membrane ST and a large diameter diffraction ST can significantly reduce mirror surface density and lower down the total mass of the ST, which offers an excellent technologic approach to earth observation. Moreover, both the launching by module and the assembly in an orbit provide the technological means to transport these kinds of observation systems from ground to GEO. Fourier telescope based on the theory of transform imaging changes the acquirement for high resolution from increasing the receiving diameter into increasing the illumination interval, and from detecting the object image directly into receiving the echo energy and reconstructing Fourier components. It breaks through the fatal bottleneck of the long range and high resolution observation. Recently, a near perfect lens has been developed to provide the possibility for breakthrough of diffraction limit, so that a new science field will be set up for super resolution observation. The perfect lens makes of negative refractive index materials(left handed materials) and the negative refractive index materials come from both of the photonic crystals and the photonic devices based on Surface Plasmon Polariton (SPP).
HAN Chang-yuan
2008, 1(1): 13-24.
Abstract(3387) PDF 399KB(2696)
Abstract:
Coming into 21 century, a number of developed countries and relational government organizations in the world, such as National Aeronautics and Space Administration(NASA) in America, European Space Agency (ESA), and some organization in Russia, have established a series of strategic projects about space science development. These projects point out some problems to be solved in space science and provide the way forward for space technology, also it indicate that development of space science is dependent on advance optical and radio telescope as well as their instruments. Therefore, this paper introduces some large astronomical telescopes used in international space science studies at the beginning of 21 century, and describes several optical systems in large aperture space telescopes mainly. Finally, the wave front sensing technique which is the key technology in the development of large astronomical telescopes is discussed.
Present status and progress in 193 nm exposure
GONG Yan, ZHANG Wei
2008, 1(1): 25-35.
Abstract(4750) PDF 331KB(4555)
Abstract:
Lithographic exposure is the key process in the manufacture of integrated circuit, and the performance of exposure system decides the level of microelectronic manufacture technology. In this paper, the present status and progress in 193 nm exposure system are described. The resolution enhancement technologies widely used in 193 nm lithography, such as offaxis illumination, phase shifting mask and optical proximity correction, are also introduced. By showing the composition and key technologies of the exposure system, the challenges in development of lithography instrument are discussed.
Development and tendency of photovoltaic concentrator system
LIU Hua, LU Zhen-wu, ZHU Rui, ZHANG Hong-xin
2008, 1(1): 49-56.
Abstract(3673) PDF 217KB(3395)
Abstract:
The development history and research situation of Photovoltaic(PV) concentrator system are briefly reported in this paper. The concentrators and solar cells for PV system are classified in detail, then their characteristicsand technological parameters are introduced. Several solar tracking systems developed by foreign countries are described, which can improve the conversion efficiency and can reduce produce cost for PV system. Moreover, two kinds of applied tendencies about PV concentrator system are discussed, they are high magnification concentrator+tracking system and low magnification and large angle concentrator+beam splitter+multisection batteries. Finally, main problems on the commercialization of PV concentrator system are presented.
Influence of defocus of exposure system on diffraction
XU Fu-quan, JIN Lu, LI Wen-hao, PEI Shu, Bayanheshig, QI Xiang-dong
2008, 1(1): 57-61.
Abstract(3438) PDF 172KB(1549)
Abstract:
As one of the important technical specifications of diffraction grating, diffraction wave front aberration directly affects the grating resolution. Recording the interference fringe produced from two coherent light beams by use of photoresist is a key process in manufacturing a holographic grating. According to the influence of defocus on collimating light parallelism of reflecting spherical collimating mirror, this paper analyzes the influence of collimating light parallelism on the wave front of holographic grating to improve setting accuracy, minimize defocus of exposure system in holographic grating, and to reduce diffraction wave front aberration of grating. The results of theoretic analysis and numerical simulation show that diffraction wave front aberration of grating is directly determined by the adjusting error of collimating mirror. In addition, by taking three kinds of gratings with different ruling densities for examples, the allowable range of adjusting error of collimating mirror is obtained.
Improvement of precision of encoder
XU Zhi-jun, HONG Xi, YU Xin
2008, 1(1): 62-65.
Abstract(3006) PDF 121KB(1488)
Abstract:
A new method based on Radial Basis Function(RBF) neural network was proposed to correct the system error of a optical encoder. The modeling method of RBF was introduced in detail and the theoretical basis for adjusting the parameters of the model was given. A new model for error correction was set up by taking the test values of the high precision instrument as outputs and the angle values of sample points as inputs. The testing results show that the precision of the encoder by this method has increased by 3 times as compared with that of traditional method and the precision of measuring system is improved greatly by using the RBF model as error compensation.
Mechanics analysis of bearing board when reproducing
SU Dong-feng, XU Zhijun, HAN Xu-dong
2008, 1(1): 66-69.
Abstract(2951) PDF 108KB(1504)
Abstract:
To reproduce the supreme diameter and high precision grating, the mechanical properties of bearing board in exposure equipment for reproducing grating was analyzed. By summing up the mechanical analysis on bearing board into a flexibility problem, the formula of the relationship between flexibility and thickness was deduced by theoretical calculation. On the basis of the formula, an exposure equipment with bearing board in thickness of 40 mm and diameter of 1 000 mm was used to reproduce a high precision and large diameter thin grating successfully, experimental results show that the biggest diameter error and uniformity error of the grating is 047″ and 8%, respectively, which can meet the requirement for angle measurement system.
A novel fitting formula for spatial concealment effect
2008, 1(1): 70-74.
Abstract(2662) PDF 160KB(1477)
Abstract:
Traditional spatial concealment effect is described by Weber law. However, it only considers photopic vision, and can not fit to weaker or stronger light intensity. In order to depict spatial concealment effect more effectively, a novel fitting formula was proposed only by signal processing method. Several different models is used to fit the data in Konig and Brodhun in experiments, and the fitted results demonstrate that the root mean square error of the proposed model is only 0010 2, which is less than those of traditional Weber law, superior form of Weber law, Guilford model, and Chen model. It can be concluded that proposed model can fit to human eyes in more expansive range of light intensity, and can be applied to engineering practice more widely.
Micro-vision measuring technology in microtarget assembling
WU Wen-rong, WU Qian, HUANG Yan-hua
2008, 1(1): 75-79.
Abstract(2963) PDF 167KB(1594)
Abstract:
To solve the problem of online measuring micro-target parts in assembling process, a micro-vision measuring system was designed and developed in this paper. The composition of miro-vision system, implementation of micro image capturing, image preprocessing, and character measurement were described. In the preprocessing, a new refiltering and denoising algorithm and a character measuring algorithm were presented for microtarget parts. Then, the system was used to measure the microtarget parts such as Al sidestep sample, and hohlraums. Experimental results indicate that proposed system can measure the geometric characters and sample positions in real time, high speed and high precision for target parts. When measuring field of view is 3 mm, the geometric measuring precision and angle precision are less than 3 μm and 01°, respectively, which shows proposed system is suitable for the assembling process of microtarget part.
MgxZn1-xO thin film and UV detector for solar blind wavelength
ZHANG Ji-ying, JIANG Da-yong, JU Zhen-gang, SHEN De-zhen, YAO Bin, FAN Xi-wu
2008, 1(1): 80-84.
Abstract(2894) PDF 148KB(2158)
Abstract:
MgxZn1-xO is a promising material for developing solarblind ultraviolet(UV) photodetectors. However, the control of the MgZnO quality and the phase separation with increase of Mg in MgxZn1-xOO alloy is still a difficult problem. Up to now, no reports that the cutoff wavelength is at 273 nm have been found for the photodetectors based on MgZnO films. In this paper, cubic MgxZn1-xOO thin films are grown on quartz and sapphire substrates by Radio Frequency(RF) magnetron sputtering and Metal Organic Chemical Vapour Deposition(MOCVD). The MetalSemiconductorMetal(MSM) structured MgZnO photodetectors are fabricated based on the films. Results from spectral analysis shows that the photodetector exhibits a peak response wavelength at 225 nm with a cutoff wavelength of 230 nm, and the cubic phase MgZnO alloy with 255 nm absorption edge is finished by LPMOCVD and the MSM devices exhibit the peak energy at 250 nm with cutoff wavelength of 273 nm, which lies in the solarblind spectrum range(220~280 nm).
Electrospinning preparation and oxygen sensing properties of dirhenium(Ⅰ) complex/polymer composite fibers
LIU Yan-hong, LI Bin, CONG Yan
2008, 1(1): 85-91.
Abstract(2749) PDF 231KB(1320)
Abstract:
A novel lipophilic dirhenium complex fac-[{Re(CO)3(d19phen)}2(4,4′bipyridylacetylene)](OTf)2,(denoted as DRe(I))(d19phen=4,7dinonadecyl1,10phenanthroline and OTf=trifluoromethanesulfonate) was doped homogeneously in polystyrene(PS) and polymethyl methacrylate(PMMA) fibers by electrospinning method and the oxygen quenching fluorescence behavior was systematically investigated. The linear SternVolmer model, the Demas and Lehrer models were used to fit the obtained SternVolmer curves of the composite fibers. An oxygen sensor based on the DRe(I) composite fibers shows short response time, good reproducible signals, and linear SternVolmer plots attributed to the existence of the ligand containing long alkyl chain groups that makes DRe(I) become soluble in the polymers.
Development of measuring instrument of optical axis parallelism for strong laser and infrared sensor
YE Lu, WU Xiao-yang, NIE Zhen-wei
2008, 1(1): 100-104.
Abstract(2682) PDF 125KB(1855)
Abstract:
A measuring instrument for optical axis parallelism was developed. By transfering laser region of 106 μm to infrared region of 3~5 μm and 8~12 μm with a heat target technique, the parallel error of optical axis between strong laser emitter and infrared sensor of a photoelectric tracking equipment was measured successfully. The structure of measuring instrument was designed as absolutely symmetrical and toy brick assembly shapes to maintain the measuring precision under the abominable conditions. Then, an ingenious electromagnetic switch was used to control and convert target surface for long distance and new assembly techniques and several check steps were taken to improve the measuring precision. Finally various environment tests were carried out to validate the reliability of measuring instrument. Experiment results show that the accuracy of the measuring instrument can reach up to 10″, also can maintain its accuracy ≤10″ under temperature of -30 ℃~+60 ℃.
A neodymiumdoped fiber laser and frequency 
SHEN Zhao-guo, ZHANG Ping
2008, 1(1): 105-111.
Abstract(3002) PDF 242KB(1841)
Abstract:
On the basis of the rate equation and the optical transmission equation for a double clad fiber laser, a mathematical model was established to calculate the output power for the optical fiber laser. Then, the distribution of output power along optical fiber and distributions of output power and pump power in different fiber lengths were simulated numerically for a neodymium doped fiber laser. By taking a 808 nm semiconductor laser as pumping source. By taking a neodymium doped double clad fiber as gain medium and KTP crystal as a multiplier, the efficiency of doubling frequency and phase angle of the laser were calculated and simulated. Finally, the frequency doubling of fiber lasers was simulated. Experimental results show that the fiber laser can achieve visible light output in high efficiency.